# CVE-2026-54900: ruby-oj: Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem

CVE-2026-54900 is fixed in ruby-oj on 1 platform, first by DEBIAN-CVE-2026-54900, released July 3, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-54900
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0052
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 1, 2026

## Description

Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.2, when in usual mode with create_id enabled, Oj::Parser#parse is vulnerable to heap corruption via a negative-size memcpy. When a JSON object key is exactly 65,535 bytes long, an integer truncation in form_attr (usual.c:63) converts the length to -1 before passing it to memcpy. This causes memcpy to copy SIZE_MAX bytes (interpreted as a huge size_t), corrupting heap memory and crashing the process. The issue has been fixed in version 3.17.2.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | ruby-oj Debian 12.15 (bookworm) | 3.14.2-1+deb12u1 | [DEBIAN-CVE-2026-54900](https://patchblox.com/security/data/fix/linux/debian-cve-2026-54900.md) | Jul 3, 2026 |
| Linux | ruby-oj Debian 13.5 (trixie) | 3.16.3-1+deb13u1 | [DEBIAN-CVE-2026-54900](https://patchblox.com/security/data/fix/linux/debian-cve-2026-54900.md) | Jul 3, 2026 |
| Linux | ruby-oj Debian 14 | 3.17.3-1 | [DEBIAN-CVE-2026-54900](https://patchblox.com/security/data/fix/linux/debian-cve-2026-54900.md) | Jul 3, 2026 |

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Data as of 2026-11-08T19:12:23Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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